Exemplary embodiments of the invention relate to a method for the open-loop control of the front light distribution of a vehicle.
Vehicles comprising front headlights for generating a defined front light distribution are known from the general prior art. Conventional vehicles typically have two different front light distributions at their disposal, known as the low beam and the high beam, which has a greater reach than the low beam in terms of its light distribution, and which also illuminates a larger region to the side than the low beam, in particular on the left-hand side facing the oncoming traffic.
It is now also known from the general prior art that almost any light distribution can be produced using what is known as a matrix headlight, for example based on a matrix of light emitting diodes or laser diodes, in order to achieve the greatest possible range of vision while not dazzling the oncoming traffic, for example.
In this context, reference can be made to DE 10 2010 048 659 A1 by way of example, which describes a vehicle illumination device that enables targeted light distribution. As a result, it is possible to distribute the light in such a way that can prevent oncoming traffic from being dazzled and enable the greatest possible range of vision for a person driving the vehicle.
A method for the open-loop or closed-loop control of an external light distribution of a vehicle is known from DE 10 2012 015 618 A1. The concept, which is primarily directed to a bus, is that different light distributions can be produced in specific traffic situations. This goes beyond the low beam and high beam light distribution which is known per se, since as the bus approaches a bus stop, for example, the light distribution is pivoted in the direction of the bus stop or a potential hazard region, in order to guarantee better illumination and to ensure that objects and people in this region can be reliably recognized by the bus driver.
It is also known from the further general prior art that vehicles are increasingly fitted with environmental sensors such that the vehicle can move partly or completely autonomously based on the data from this environmental sensor system. Completely or partly autonomous driving of this kind can be achieved, in particular, on the basis of camera systems, in this case particularly stereo cameras, which can recognize objects, typically those in front of the vehicle, during a regular journey. The vehicle can then, using the data about these objects that was detected by this environmental sensor system, react accordingly and brake, swerve or the like, for example. The aforementioned cameras, in this case particularly stereo cameras, by means of which it is possible to estimate the distance to the object, have proved to be a very reliable resource for the detection of objects. In practice, however, the cameras, particularly in the dark, are dependent on the illumination from the vehicle, for example from the low beam or high beam, in order to recognize objects.
Exemplary embodiments of the present invention are directed to an improved method for the open-loop or closed-loop control of the front light distribution of a vehicle compared to the prior art.
In the method according to the invention, the vehicle has front headlights by means of which the light distribution can be changed, as described by way of example in the prior art mentioned at the outset. The vehicle also comprises an environmental sensor system that is used for at least partially autonomous driving. This environmental sensor system has at least one optical camera, which is preferably intended to be designed as a front stereo camera.
According to the invention, when the front light is switched on during an at least partially autonomous driving operation, a different light distribution is produced than during driving operation when a person is driving the vehicle. The inventor has recognized here that the light distribution requirements of a person driving the vehicle are in principle different to the light distribution requirements of an optical camera. Using different light distributions depending on whether the vehicle is being driven by a person or is driving partially or completely autonomously, it is now possible to adapt the light distribution to the specific needs of the person and the optical camera. This is used in particular to produce illumination by means of the front light distribution of the vehicle, which illumination is optimized for the camera during autonomous or partially autonomous driving. As a result, earlier recognition of objects and improved recognition of the object type and the distance to the object is made possible such that an improvement in autonomous or partially autonomous driving and particularly in safety is made possible overall.
It is usually the case that the conventional light distribution, both of the low beam and the high beam, is adapted to the typical angle of vision of a person who is driving the vehicle. The angle of vision of an adult person is typically approximately 150°, and therefore the light distribution corresponding to this angle of vision of the human eye is selected to be comparatively wide such that, as far as possible, the entire visual range of the person driving the vehicle is illuminated.
According to one very advantageous development of the method according to the invention, a smaller beam angle for the light distribution is provided for the event that the vehicle is being driven autonomously or partially autonomously, in addition to this relatively wide light distribution if a person is driving the vehicle. Compared with the angle of vision of the human eye of approximately 150°, the angle of vision of a camera is comparatively restricted to typically approximately 60° to ensure a sufficient quality of recognition. It is therefore also sufficient to implement a light distribution at a correspondingly small beam angle, because it is now not necessary to illuminate the entire angle of vision of the human eye, but only the angle of vision of the camera. However, this type of more strongly focused light beam of the light distribution now facilitates, according to one advantageous development of the method according to the invention, a greater light range than the light distribution when a person is driving the vehicle themselves. The camera can therefore see further ahead than a person could.
The environmental sensor system of a vehicle that is used for autonomous driving in practice very often has, in addition to the optical camera, at least one additional sensor, in particular a radar or lidar system, or even a laser scanner or the like. According to an extremely advantageous development of the method according to the invention, in the event that the environmental sensor system has at least one additional sensor, if an object is detected by the additional sensor, but not by the camera, the light distribution is changed in such a way that the object recognized by the additional sensor is illuminated. For instance, if the additional sensor of the environmental sensor system is a radar, it is possible to “see” a lot further than the conventional light distribution reaches and also in particular then the light distribution of the method according to the invention during autonomous driving reaches. According to this advantageous development of the method according to the invention, if an object is identified by the radar, which object for example is situated in a poorly illuminated edge region of the road, then this object detected by the additional sensor can also be illuminated by means of the front headlights and a change of the light distribution and/or by means of an additional headlight which provides a targeted focused light cone by means of a light element. An illuminated object of this kind is now reliably detected by the camera of the environmental sensor system as there is now enough light available. As a result, the recognition precision is correspondingly improved inter alia by the redundancy of the additional sensor and the camera. A distance estimation can also be carried out redundantly when a stereo camera and the radar are used.
According to another advantageous embodiment of this concept, the recognized object is not selectively illuminated when the recognized object is a moving vehicle. It would be conceivable for the oncoming vehicle or vehicle in front to be dazzled as a result. A vehicle of this kind should generally be recognized due to its own illumination, its speed of movement and its movement vectors, such that in this situation the targeted illumination can cease.